Door lock switch



Nov. 10, 1942. s. K. KNIGHT DOOR LOCK SWITCH Filed Dec. 5, 1941 571650557 mz ha INVENTOR.

mm mm Patented Nov. 10, 1942 UNITED STATES PATENT OFFICE This invention relates to a door lock switch and has for an object to provide an electric switch combined with a door lock in such a manner that when the door is locked from the outside the electric current is cut oil from the lights in a room, home, store, or any place where lights may be inadvertently left burning when there is no one present, while if the door be locked from the inside the electric circuit to the lights is not disturbed.

A further object is to provide apparatus of this character which will be formed of a few strong, simple and durable parts, which will be inexpensive to manufacture, and which will not easily set out of order.

with the above and other objects in view the invention consists of certain novel details of construction and combination of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claims without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawing forming a part of this specification:

Figure 1 is a longitudinal section through a door lock, and the parts of the door and door frame adjacent thereto together with the switch and operating means therefor constructed in accordance with the invention, the lock bei shown as locked by a key from the outside and the switch being shown in open circuit position.

Figure 2 is a view in elevation of the lock with the parts shown in unlocked position and showing the switch operating plunger in inoperative position.

Figure 3 is a detail perspective view of the head portion of the switch operating plunger.

Referring now to the drawing in which like characters of reference designate similar parts in the various views, ll designates the barrel of a cylinder type door lock, the same having a rotatable arm ii turned in the direction of the arrow head in Figure 2 when the key is operated from the outside to move the locking bolt i! to projected position from the door II into the keeper il in the door frame I 5.

The lock bolt, in the present embodiment, is provided with a pivoted arm I having a projection I! in the path of the rotatable arm H and adapted to be struck by the arm to swing the pivoted arm i6 downward against the tension of its controlling spring ll so that a stop lug it on the pivoted arm ll clears an abutment II in the lock casing II to permit the lock bolt ii to be '(CI. lot-54) moved from the unlocked position shown in Figure 2, to the locked position shown in Figure 1 by the continued swinging movement of the rotatable arm il striking against a shoulder 21 on the look bolt and bodily moving the lock bolt into locked position.

During further continued movement of the rotatable arm Ii when the door is being locked from the outside the switch mechanism will be l0 opened as will now be described.

A switch operating plunger 23 is slidabLv mounted in a guide 24 carried by the lock casing 2i and is adapted to .be proiected from the casing into an opening formed in the door where it operates the push button 26 of a conventional switch 21 having fixed contacts 28 and a pivoted bridging contact arm 28 carried by one of the fixed contacts and adapted to engage the other. A spring 30 back of the contact arm normally holds the contact arm normally holds the contact arm in circuit closing position to maintain the electric circuit 3| for the lights to be controlled, closed at the switch. The push button 28 when moved by the plunger moves the contact arm 29 to open circuit position to open the light circuit ii at the switch when the door is locked from the outside.

The plunger 26 is provided with a transverse head 32, and is also provided with an abutment 50 pin 34. During final stages of movement of the rotary arm II the arm will ride oil the shoulder 22 and onto an arcuate surface on the plunger head 32 and move the plunger head in a rectilinear direction to correspondingly move the switch 35 operating plunger 23 and open the switch 21.

all helical spring 36 is sleeved on the plunger between the guide 24 and the abutment pin 34. The spring is compressed when the plunger is moved to open the switch so that when the door 40 is unlocked from the outside by a person entering the room the spring will expand and cause the plunger head to move back to initial position to withdraw the plunger from against the push r button 28 and permit the spring ll of the switch to close the switch so that the lights in the room may be operated by the conventional room switch after the person enters the room.

The plunger is provided with a notch II which is engaged back of a stationary guide 38 when the door is locked from the outside by the rotatable arm li swinging the plunger head upwardly by upward pressure thereon as the arm rides up the arcuate surface 35 of the plunger head. The

guide holds the plunger in position to hold the contact arm 29 in open circuit position until the door is unlocked irom the outside. At such time the rotatable arm II will swing downward and strike the projection II to depress the pivoted arm II and disengage the stop lug ll irom'ln front or the abutment ll. During further movement the rotatable arm strikes against a protection 80 on the-lock bolt l2 andbodily retracts the bolt from the keeper ll. 'I'hereupon a spring finger ll, carried by the lock bolt passes into a slot H iormed in the plunger head I! and contacts with a transversely disposed pin 42 in the slot to pull the plunger downward and release the notch 81 from the guide II and permit the spring I to expand and move the plunger to initial position, at the same time permitting the switch spring 8| to move the contact arm II to circuit closing position so that the lights may be operated by the conventional room switch.

The lock bolt It may be locked by the thumb control ll from inside the room without disturbing the closed circuit position oi the switch alter the door has been unlocked from the outside and person enters the room. This is accomplished by the spring linger ll loosely ntting in the slot ll in the plunger head, out 01' engagement with the pin I! when the door is unlocked so that it rides in a rectilinear direction out of the slot ll when the lock bolt is locked without disturbing the plunger head or arm The same is true when the ilnger moves into the slot 4| when the lock bolt is retracted by the thumb control.

The thumb control comprises a pair of horns 42 which selectively engage a projection 48 on the wall of an oval opening 44 formed in the lock bolt. when the thumb control ll is rotated in the direction of the arrow head shown in Figure 2 one of the horns will engage the projection and slide the lock bolt to the locked position shown in Figure 1. Said horn will engage a stop ll on the lock casing II at its limit of movement. When the thumb control is rotated in the opposite direction the other horn will engage the projection 43 and retract the lock bolt from the position shown in Figure 1 to the position shown in Figure 2. It is to be understood that during such rotary movement the thumb control is slid in a rectilinear direction in either case. to pass over the projection 41 and rock the pivoted arm ll downward to disengage the stop lug II from the abutment 20 to permit operation or the lock bolt as Just described.

Since the operation of the parts has been described as the description of the parts progressed it is thought the invention will be fully understood without further explanation.

What is claimed is:

'1. In a door lock switch for room circuits, the combination ot a bolt, a lock barrel having an arm rotated by a key inserted from outside a room to lock and unloit the bolt. a spring pressed plunger having a transverse head provided with an arcuate surface engaged by said arm subsequent to the locking of the bolt to move the plunger pivotally and endwise. a normally closed push button switch for controlling a room circuit moved to opencircuit position by endwise movement of the plunger, detent means cousins the. plunger upon pivotal movement oi! the. plunger ior'freleasably holding the switch open. and means carried by the bolt engaging the'plunger head to move the plunger pivotally and release the detent means subsequent to unlocking oi the bolt to permit the switch to return to normal closed position.

2.!hsstruciureasoiclaim l andinwhich said detent means comprises a notch in the plunger and a stationary guide engaged in said notch by pivotal movement of the plunger under urge of said rotating lock arm.

.3. The structure as of claim 1 and in which the last named means comprises a linger having a portion extending along the bolt and spaced from the bolt adapted to enter a recess in the plunger head, and a transversely disposed pin in the recess engaged by said linger to rock the plunger and move the notch out of engagement with the guide when the bolt is unlocked by the rotating arm..

4. In a door lock switch for room circuits the combination of a bolt, a lock barrel having an arm rotated by a key inserted from outside a room to lock and unlock the bolt, a thumb control means for locking and unlocking the bolt independently oi the arm from outside the room, a spring pressed plunger having a transverse head provided with an arcuate suriace engaged by said am subsequent to the locking of the bolt to move the plunger endwise and pivotally, a normally closed push button switch for controlling a room circuit moved to open circuit position by endwise movement of the plunger, a notch in the plunger, a stationary guide engaged in said notch by pivotal movement of the plunger under urge oi the rotating lock arm, a finger carried by the bolt extending along the bolt and spaced from the bolt adapted to enter a recess in the pivoted head, and a transversely disposed pin in the recess engaged by said tinger to rock the plunger and move the notch out of engagement with the stationary guide when the bolt is unlocked by the rotating arm to permit the switch to return to normal closed position, said finger entering the recess without engaging the pin when the thumb control means is used to open and close the bolt Irom inside the room and not efl'ect nz the released position of the push rod so that the switch may remain closed.

SHELDON K. KNIGHT. 

